Brake



Feb. 27, 1940., R BOLSTER 2,192,001

BRAKE Filed Nov. 25, 1938 2 Sheets-Sheet 1 A TTORNEY.

Feb. 27, 1940. R. H. BOLSTER BRAKE Filed Nov. 25, 1938 2 Sheets-Sheet 2 INVENTOR. fia/mw/ziazsrifi ATTORNEY ca ra. 27, 1940 I 2,192,001

BRAKE Ronald ,I-I. Bolsters Buchanan, Mich, assignor tov Clark Equipment Company, Buchanan, Mich, a corporation of Michigan UNITED STATES PATENT OFFICE Application November 25, 1938, Serial No. 242,176

Claims. (01.,188-78) This invention relates to brakes, and more Figure. 3 is a top plan view of the brake apparticularly is directed to the adaptation of a plying mechanism; I

parking brake actuating mechanism to the hy- Figure 4. is a partial elevational view of the ,draulic brake structure. brake ofFigure 1 in expanded position; and -5 As is well known, hydraulic brakes in them- Figure 5 is an enlarged sectional View taken 5 I selves cannot be used as parking or emergency substantially on line 5-5 .of Figure 3.

brakes, since the slightest leakage of the brake Considering now in detail the drawings, there fluid releases the braking pressure of the shoes is provided a backing plate 5 having the periphagainst the drum. As a result, it is necessary eral flange 6 within which is disposed the lateral 0 to provide a mechanical linkage operated from edge ofa brake drum (not shown), and the offa hand lever for setting the brakes manually. set central portion lhaving the circumferential This linkage must include means within the series of openings, 8 adapted to receive securing brake drum housing for mechanically expanding ,meansfior attaching the backing plate to the the brake shoes against the drum. brake flange of an axle housing arm or wheel '15 The present invention n p at s a s p spindle. Pivotally mounted .within the periph- P y, the present invention Consists of of the shoes 9 has a boss portion l2 at one end p arrangement Which can readily be cry of the backing plate 5 are a pair of brake .mounted within the available space between the shoes 9.having the brake lining H] on the ar shoes n he backing p and i x r m ly ate outer surface thereof adapted to be forced economical to manufacture and easy to assemble. into, engagement with the brake dr E h tWO arms Supported Oh the backing plate and thereof, which portions are mounted on studs having cam po s at their adjacent ends or anchorv bolts l3 extending through the brake w n Wh i disposed an. Operating l ver X- plate and h aving suitable nuts 14 for securing tending Out to h b d Side O e backing them in position.- The studs l3 preferably have plate. Suitable cable or linkage connection from projecting sl pped efi. ends l5 whereby they may 25 the lever to the hand control lever completes the be t t d t adjust the position of the shoes, mechanism. the bearing portion about which the boss I2 of one Of e main Objects of the present the shoes engages being eccentrically disposed vention resides in thev provision of such mechaith respect t the axis of the stud. The shoes '3 IliSm pp ed entirely on the hacking Plate are guided for expanding movement on suitable and requiring I10 enclosing housing the likestuds 5' projecting through the backing plate A oth o j t of t pr invention is the and received within slots 11 formed in the shoes. design of a mechanism of s pe which l Suitable adjusting cams [8 are provided which transmit equal pressure to each brake shoe. This may b t t d from the inboard side of the is accomplished by Providing a floating pivot backing plate to move the shoes toward and 5 5 e Operating whereby the reaction of the away from the the brake drum as the lining Ill arm's against the shoe determines the center wears down, h 01 the hoe is preferably of ota O the provided with a boss portion 20 apertured to Still another feature of the present invention 7 receive. the d of 9, il spring member 22 resides in the design of a structure in which all extending between the shoes and normally tyend parts can be e from metal Stampihgs, and ing to contract the same out of engagement with no machine operations are necessary prior to the I h brake drum i I es e b ye S StemplhgS- At their upper ends the shoes are provided other objects and advantages of the present with arcuately recessed end portions Z3 which invent on W l e more apparent f the are'adapted to. receive the extending pin ends lowing detailed description which, taken in con- 24 i th i ton r ds 25 pr jecti int th hyu t with t mpanyin drawings, w ll draulic cylinder 26; The hydraulic cylinder 26 disclose to those skilled in the art the particular 1 f t e ti l type d i mounted on construction and operation of a preferred form t backing plate by means of th b pgrtiong of my invention. 21, which are tapped to receive the cap screws 50 on line 2-2 of Figure 1; i

, In the drawings: 28. It will be apparent that when fluid is forced Figure 1 is an'elevational view of abrake eminto the cylinder 26 under pressure the piston bodying the present invention; rods 25 are expanded or moved outwardly of the Figure 2 is a sectional view taken substantially ends of the cylinder, thereby applying pressure r i to the ends 23 of the brake shoes forcing these -55 shoes to expand into frictional contact with the.

a curved end portion 36 adapted to engage the. flange 31 of the respective brake shoes, this flange being formed adjacent the upper end of',

the boss portion 20. The opposite ends of the arms 34 and 35 are provided"wi'th j'arcuate cam ends 38 and 39 respectivelylwhichare adapted to be pinned by pins 49 between two disc-shaped washers 42 and 43. Thewa'sher 43 rests upon the shelf portion 32 of the member 33 and there-, by supports the arms 34 and 35 against movement out of planar relationship. Suitable guide members 44 are Welded to the backing plate 5 above the offset portion 7 thereof, and are suitably apertured to receive the extending portions of the arms and to guide the same for movement transversely-ltherethrough.

Intermediate the cam ends of theiarms there is provided a brake operating lever, indicated generally at 45, having a camportion i3 adapted to engage the cam end 33 of the arm',34 and a cam portion 41 adapted to engage "the cam end'39 of the arm 35. The lever 45 is pivotally mounted on a pin 63 having, a head portion en-' gaging the under surfaceof the shelf portion 32 of the support 30 and extending through the two washers l2 and 43 and through the arm 45 intermediate the cam portions 43 and 41 thereof. The shelf portion 32 is preferably apertured and provided with a longitudinally extend,- ing slot 53 allowing for slight longitudinal movement of the pin 43 therein, and thereby providing a floating support for the pivot of the lever 45. upper surface of ,the washer 42, and is held in position by a suitable spring clip member 52 engaging in a groove therein, this being sufficient inasmuch as there is no axial thrust of the mechanism along the pin 43.

The backing plate 5 is provided with a longitudinal slot 55 to accommodate the arcuate movement of the lever 45 in the brake applying and releasing positions, and this opening is, preferably covered by a cover plate 56 whichclosely fits about the arm 45 inwardly of the boss 5'! and has sliding movement .over the inboard surface of the backing plate as the lever arm is rotated about its pivot.v A suitable spring clip 54 is biased against the plate 56 to hold it firmly against the surface of the backing plate to prevent rattling thereof and to prevent possible dis placement of theplate 55, which might allow dirt or water to enter the opening 55.

The outer end. of the lever is ,apertured toreceive a suitable clevis 58 to which is connected a cable 59 leadingto any suitablebrake applying means; such as a hand brake lever, parking brake lever, or the like. 1 v

In the operation of the mechanism thus far described, the tension on the cable 59 results in rotating the arm 45 about the pivot pin 48. This produces pressure of the cam surfaces 46 and 41 against the lever ends 33 and 39 of the arms 34 and 35. engage the flanges 31 of the shoes 9, thereby exend g t e oe s the p essure ofspring The pin 48 projects upwardly beyond the.

These armsshift longitudinally to 22. The pins 40 prevent any possible displacement of the lever ends 38 and. 39 out of the cam notches or recesses 46 and 41 of the lever 45,

since the pins are carried by the washers 42 and 43 which in turn are secured on opposite faces of the lever 45 by means of the pin 48. By reason of the slot 50 in the supporting flange 32 of the member 36 it will be apparent that the applying pressure of the arms 34 and 35 against the brake shoes 9 will be equalized since the pin 48 can shift longitudinally in the slot so that 'it will find a position wherein equallized pressure is applied by each of the arms of the lever 45. This insures equalized pressure of the arms 34 and 35 against the shoes 9 when the park- By reason of the spring clip 54 engaging the cover plate 56 the entrance of water or dirt into The two guides '15 ing or emergency brake mechanism is actuated..-

44 secured to the backing'plate serve to locate,

the arms 34 and 35 so that they will apply prop-- er expanding pressure against the shoes, and also serve to hold the ends of the mechanism so that no center buckling will occur which might 1 place an axial stress on the pin 48 holding th actuating parts together.

-As shown in Figure 4, the-hydraulic brake 30 a normal surface braking operation. It will be mechanism in this figure has been expanded in noted that this leaves the ends of the arms 34 and 35 out of engagement with the brake shoes 9 as the shoes have been moved away from the arm ends. However, when the cylinder26 is not subjected to fluid pressure and the pistons 25 are retracted by reason of spring 22, operation of the lever 45 will produce a braking apdraulic actuating mechanism.

It is therefore believed apparent that I have provided a novel type of mechanical brake applying mechanism to be employed in conjunction with hydraulic brake assembly, which is simple in design, can be readily manufactured from stampings, and can be easily assembled into the space now available in, the conventional type of hydraulic brake construction.

I am aware that various changes may be made in certain details of the present invention Without departing from the underlying principles thereof, and I therefore do not intend to be limited except as defined by the scope and spirit of the'appended claims.

I claim:

1. A brakeactuating mechanism including two fiat coplanar brake shoe engaging arms having adjacent oppositely curved ends, a lever extending in the plane of said arms and pivoted therebetween, said lever having cam portions on opplication similar to that produced by the hyi posite sides of its pivotal support engaging said arm ends, and means overlying said cam portions and arm ends and pinned to said arm ends for rotation about said lever pivot. uponactuation of the lever for maintaining said arm ends said arm ends, a pivot for said lever intermediate said arm ends, means supporting said pivot and allowing movement thereof longitudinally relative to said arms whereby upon rotation of ver. 3. In combination, a brake backing plate hav- 'ing a pair of brake shoes pivoted thereon, spring said lever for camming-said arms in opposite directions said pivot will move into an equalizing position in said supporting means, and means connected between said lever pivot and said arm end portions preventing movement of said arms out of planar alinement with said lemeans normally tending to contract said shoes,

. a support intermediate said shoes, a guide secured to said plate intermediate each shoe and said support, co-planar arms each extending through one of said guides and having a curved end overlapping said support, a pair of circular washers overlying the ends of said arms and pivotally connected thereto, and a lever pivoted 4. In combination, a brake actuating mechanism comprising an actuating lever, a fixed support having a slot therein, a pivot for one end of said lever guided in said slot, a pair of oppositely extending arms each having a curved end portion engaging the-lever on opposite sides of the pivot thereof, whereby rotation of the lever will move said arms in opposite directions, fixed means guiding the opposite end of each arm,

and means carried by the lever pivot overlying said arm end portions and pinned thereto preventing disengagement thereof from said lever and maintaining the same in coplanar alinement. I

5. In combination, a brake actuating mechanism comprising an actuating lever, a fixed support having a slot therein, a pivot for one end of f said lever guided in said slot, 21; pair of oppositely extending arms each having a curved end portion engaging the lever on opposite sides of the pivot thereof, whereby rotation of the lever will move said arms in opposite directions, and

means carried by the lever preventing disengagement of said arms therefrom.

RONALD H. BOLSTER. 

